NSDictionary *json = @{
            @"phoneNumber" : @"123-555-6789",
            @"name" : @"Johnny Ringo",
            @"age" : @"BANANA",
            @"weight" : @"130.3",
            @"ssn" : [NSNull null],
            @"children" : @[],
            @"parents" : @[
                    @{
                            @"name" : @"Mickey"
                    },
                    @{
                            @"name" : @"Minnie"
                    }
            ]
    };

BOOL validated = YES;

NSString *phoneNumber = [json objectForKey:@"phoneNumber"];
if(!phoneNumber || ![phoneNumber isKindOfClass:[NSString class] || [phoneNumber length] < 7) {
  NSLog(@"Phone number didn't validate (not found or not an NSString or length < 7)");
  validated = NO;
}

NSString *name = [json objectForKey:@"name"];
if(!name || ![phoneNumber isKindOfClass:[NSString class]) {
  NSLog(@"Phone number didn't validate (not found or not an NSString)");
  validated = NO;
}

NSNumber *age = [json objectForKey:@"age"];
if(age && ![age isKindOfClass:[NSNumber class]) {
  NSLog(@"Age exists but didn't validate (not an NSNumber)");
  validated = NO;
}

NSNumber *weight = [json objectForKey:@"weight"];
if(weight && ![weight isKindOfClass:[NSString class]) {
  NSLog(@"Weight exists but didn't validate (not an NSString)");
  validated = NO;
}

NSString *ssn = [json objectForKey:@"ssn"];
if(ssn != [NSNull null]) {
  NSLog(@"ssn should be null");
  validated = NO;
}

NSString *height = [json objectForKey:@"height"];
if(height && ![weight isKindOfClass:[NSString class]) {
  NSLog(@"Height exists but didn't validate (not an NSString)");
  validated = NO;
}

NSArray *children = [json objectForKey:@"children"];
if(children && ![children isKindOfClass:[NSArray class]) {
  NSLog(@"Children exists but didn't validate (not an NSArray)");
  validated = NO;
}

NSArray *parents = [json objectForKey:@"parents"];
if(parents && ![parents isKindOfClass:[NSArray class] && [parents count] <= 1) {
  NSLog(@"Parents exists but didn't validate (not an NSArray or count <= 1)");
  validated = NO;
}

NSError *error;

[RPJSONValidator validateValuesFrom:json
                   withRequirements:@{
                           @"phoneNumber" : [RPValidatorPredicate.isString lengthIsGreaterThanOrEqualTo:@7],
                           @"name" : RPValidatorPredicate.isString,
                           @"age" : RPValidatorPredicate.isNumber.isOptional,
                           @"weight" : RPValidatorPredicate.isString,
                           @"ssn" : RPValidatorPredicate.isNull,
                           @"height" : RPValidatorPredicate.isString,
                           @"children" : RPValidatorPredicate.isArray,
                           @"parents" : [RPValidatorPredicate.isArray lengthIsGreaterThan:@1]
                   } error:&error];

if(error) {
    NSLog(@"%@", [RPJSONValidator prettyStringGivenRPJSONValidatorError:error]);
} else {
    NSLog(@"Woohoo, no errors!");
}

NSDictionary *json = @{...};
NSError *error;

[RPJSONValidator validateValuesFrom:json
                   withRequirements:@{...}
                              error:&error];

NSLog(@"%@", [RPJSONValidator prettyStringGivenRPJSONValidatorError:error];

// Output:
// 2014-03-19 23:08:02.451 RPJSONValidator[42273:60b] 
// * age
//      * Requires NSNumber, given (__NSCFConstantString)
// * height
//      * Key not found
// * parents
//      * Requires NSString, given (__NSArrayI)
//      * Requires length or count less than or equal to (3)

NSDictionary *json = @{
        @"car" : @{
                @"make" : @"Ford",
                @"model" : @"Mustang"
        },
};

[RPJSONValidator validateValuesFrom:json
                           withRequirements:@{
                                   @"car" : @{
                                           @"make" : [RPValidatorPredicate valueIsEqualTo:@"Ford"],
                                           @"model" : [RPValidatorPredicate valueIsEqualTo:@"Mustang"]
                                   }
                                      error:&error]

NSDictionary *json = @{
        @"cars" : @[
            @{
                 @"make" : @"Ford",
                 @"model" : @"Mustang"
            },
            @{
                 @"make" : "Tesla Motors",
                 @"model" : "Model S"
            },
            ...
        ],
};

[RPJSONValidator validateValuesFrom:json
                           withRequirements:@{
                                   @"cars" : @{
                                        @0 : @{ // Access the first element
                                             @"make" : RPValidatorPredicate.isString,
                                             @"model" : RPValidatorPredicate.isString
                                        }
                                   }
                                      error:&error]